Metallic treatment of vitreous materials



March 24, 1936. R SCHlRMER I I 2.035,015

METALLIC TREATMENT OF VITREOUS MATERIALS Original Filed Dec..1, 1930 I NVEN TOR.

R 5 ScH/RMER BY MM KW A TTORNEY.

Patented 24, 1936 i ETALL C TREATMENT or vrri'mous MATERIALS" Bens E.Schirmer,New York, l\l. Y.- .1 I

4 Claims. (01 91'l0.1)

This invention relates to a method ofmetallizing the surfaces ofvitreous materials, such as glass, porcelain, quartz, etc., to provide ametal coating thereon and in intimate and unitarycon- 5 tact therewith.Such a coating is not only highly desirable' for certain purposes butis'positively essential for the performing of certain operations 'orfunctions, among which may be mentioned the forming of sealing contacts,heat conductive pur- 10 poses, increasing tensile strength, providingornamental effects, etc. The primary object of my invention is toprovide a new and improved meth-; od of producing such metallic coatingsin intimate and securecontact with vitreous surfaces.

15 I am aware that metallic coatings have been prqvided on vitreoussurfaces by the use of adhesives but such'coatings have not been inintimateand unitary contact with the vitreous surfaces, and are quitereadily removable particu- 20 larly under the action of heat. I alsounderstand that some 'of-fthe rare-and noble metals, such as gold-and'platinum,'-which are oxidizable only at very high temperatures.have heretofore beenapplied directly toFvitreous'surfaces but the :5 useof such process has been extremely limited,

particularly due to the high" cost of these metals. My'inventioncontemplates theuse of the more common or base metals, such-ascopper,"silver, nickelyetcg which oxidize relatively easily. Inaccordance with my invention, I first apply the metal in oxide form tothe surface to be coated and so heat treat this surface that the oxideimpregnates into the surface to form a physicalchemical union therewithand therebeneath. I 3-3 thereafter subject this heated surface to a'reducing atmosphere which reduces the exposed oxide to its metallicstate in a manner leaving a pure metal coatingon said surface and inintimate union with the impregnated metal in the 40 vitreous bodybeneath its surface. Such an improved method of metallizing vitreoussurfaces by the use of the base metals to provide a layer of such metalon and in intimate contact therewith comprises a further object of myin- 45 vention. I

In the accompanying drawing I have illustrated one simple way ofcarrying my invention into practice but it will be understood that theinvention can be otherwise embodied and that the 50 drawing is not to beconstrued as defining or limiting the scope ofrthe invention, the claimsappended hereto being relied upon for that purpose. 7 I

Referring to the figures of the drawing,

55 Fig. 1 illustrates the heat treatment of a coated'vitreous surface inaccordance with my invention; j

Fig. 2 illustrates-thereducing of the treated I surface to provide'ametallic coating thereon; 1

' My -invention particularly contemplates the coating of the surfacesof'vitreous bodies with the morefcomrnon andcheaper base metals in suchmanner thatthe metal will form an intimate and unitary contact with thebodies and render the surfaces for most purposes substan- 10 tiallythe'same as though' the entire body were of metal. I- have'in theaccompanyingdrawing ratherl diagrammaticallyillustrated the steps ofmy-process-and in defining the invention herein Ishall briefly referto-this drawing.

I Proceeding with the descriptionof my'proces's, I'take afinely'po'wdered oxide of the desired metal and intimately mix the samewith a suit able liquid vehicle or carrier, whereby to form a paint-likepaste. Inemploying my invention, I a

have most commonly usedcuprou's oxide intimately "mixedwith oil oflavendenlbalsam tor. the like. I then*paint,'spray, orin any othersuitable man ner apply a coating of the mixture to the'vitreous surfaceto be metallized "The coating isthen dried the vehicle or oildissipating and leaving on the-vitreous surface a'uniform coating of theoxide. I then introduce'the coated surface into a flame or other heattreating apparatus or means,

whereby its temperature is raised to the point wherein the oxide willchemically unite with the vitreous material on and beneath its surface,this usually being to a red or somewhat hotter heat.

The temperature of this heat treatment should be high enough to bringthe oxide to its molten or plastic condition, whereby the oxidemay bereduced to relatively pure metal in the subsequent operation which Iam'about to describe. The

' duration of this heat treatment should be sufflcient tojallow thechemical union to be carried 40 out and this ordinarily takes but a fewmoments. Preferably directly following this treatment and withoutpermittingthe surface to cool, I quickly introduce the heated surfaceinto a reducing atmosphere, such as hydrogen gas,-- whereupon the duced.into a flame which may be anordinary Bunsen burner or any burnerwhichwill give the required temperature, it being understood that thetemperature required will vary with the metal used and with thecharacter and size of the vitreous material. After the end 2 has beensufficiently treated in the flame, it is quickly introduced into a tube4 through which is flowing a stream of hydrogen or other gas of areducing nature, the gas escaping. fromth'is tube "burning at the end 5'thereof.. I have found ordinary illuminating gas very satisfactoryv forthis purpose. The tube may be placed on a pair of rests 6 and is allowedto cool in thereducingatmos phere. After this cooling operation, thetreated surface of the tube I will be found to have'a coating of purecopper metal in'intimate contact with the vitreous bodyandin chemicalunion with the copper impregnated thereinto. The thickness of thiscopper coating'will to a limited degree depend upon the amount of copperoxide which was originally coated upon the tube at 2. The copper surface1 will,'furthermore, be

found to have substantially all, the properties of a solid copper tube,such as permitting soldering or fusing thereonto, a conductor ofelectricity, heat transmission, etc. a

While I have herein more particularly referred to copper and totreatment by-the use of apparati such as illustrated in, the drawing, itwill be understood that anysuitable metal maybe used in the process andthat'any sourceof heat, such-as electrical or an electrical or fuelfired furnace may be used. Furthermore many other variations thereof canbe used without departing from the spirit of the invention, particularlywhen adapting the process to the use of automatic machine methods. Itwill also be understood that instead of introclucing the treated tube[into a reducing atmosphere, the reducing atmosphere may be introducedinto the kiln or like apparatus iniwhich the tube is heattreatedp Havingthus described my invention, what I claim as new and desire tosecureby-Letters Patentis: a g

1., A method of providing alayerof pure base metal on the surface of avitreous body and intimately combined with the body beneath its surface,consisting of coating ,the-surface; with a. paint-like substancecomprising an oxide of the metal in a liquid vehicle,"heat treating thecoated surface at a temperature causing a portion of the coating toimpregnate into and unite chemically with the body beneath its surface,and thereafter subjecting the heated surface to a reducing atmosphere torender the resulting ex-' to a temperature sufiicient to cause a portionof the oxide to impregnate into the body beneath its surface, andreducing the resulting exterior portion of the coating to a purelymetallic state by subjecting it in heated condition to a reducingatmosphere.

-3. A'method of providing a layer of pure base metal on the surface of avitreous body and intimately combined with thebody beneath its surface,consisting of coatin'g'the surface with a paste-like mixture v compr s gan oxide. of the metal in a suitable vehicle, evaporating the vehicle todry'the coating, heattreating the coated surface at a temperaturecausing a. portion of the coating to impregnatefinto and unite chemi:cally with the body beneath its surface, and thereafter subjecting thecoated surface in heated condition to a reducingatmosphere to render theexterior portion of. the coating P rely metallic and in chemical. unionwith said coating impregnated beneath the surface.

4. A method of providing a layer of predetermined thickness of. purebase metal on and in intimate contact with the surface of a vitreousbody, consisting of mixing an oxide of the me'tal in a suitable liquidvehicle toform a semi-liquid paste, coating the surface with the ,pasteto a. depth in accordance with-the-thicknes's of metal coating it isdesired to produce, heat treating the coated surface in aiiame to 'atemperature causing a portion of, the coating to'impregnate into andintimately .combineiwith thebody, and thereafter subjecting theheatedsurface to a reducing atmosphere to render. jtheexterior'portion of thecoating purely metallic,

. 4 REN S E.- SCH IRMER.

